Automatic reverse brake



April 28, 1936. LEsTl 2,038,663

AUTOMATIC REVERSE BRAKE Filed April 26, 1935 FIG. I.

INVENTOR Patented Apr. 28, 1936 UNITED? EAT ENLT oral-ea halfi tor. Nathan W. Calif,

Schireson; .Los Angeles,

Claims.

Theinvention relates to anautematicreverse brake system" for veliicles a-nd' is particularly adapted-to automobiles: In thesevehicles-this system may-be used-advantageously in-th'e"con 5- ventional "transmission. 7 7

An object- 0fmy invention-is to automatically prevent vehicles from moving -ir'r -the reverse di rection: when they-areabout tobe startedmoving in .the forward direction; Vehicles, particularly automobiles; reverse --in this fashion prior tothe application: of f or-warddriving-power and after the release oftheconventional brakes when the vehicle. is about'to-bestarted moving up-roadswith .a grade. This is asource-of-annoyanceand -1oss o:time to thedriver: It leadsto accidents and requires expert handling ofthe vehicle to prevent and usually causes -undue-- wear= ofitsparts.

Another. object of this-invention is-to automatical1y provide-sufiicient braking-power to an automobile. just when it stops, after moving up a-road,with .agrade, so that thewehiclewill not move in the reverse direction"priorto-the-application of :the conventional brakes;

Another-object of this invention is to provide sufiicient braking power for automobilesso as to .assist the conventional emergency brakes and act asan additional emergencybrake ifthevehicle has ,amtendency to move in the-reverse direction. and. the normal brakes are not operating;

This feature is :useful. when-traveling in hill or mountain roads.

In this connection, a furtherdetailedob'ject of I my invention-is to permit reverse motion of the vehicle when. the: same is 1 hit "with great force-'- tending vto :cause reverse ,motion. This a featureis necessary in order to protect various axles and gears. which would otherwise I be subjected to--- breaking strains if the above mentioned features "-alone were-working.

Another object ".of-pthis: invention -is to provide a mechanism which is relatively simple quietand is :-not subjected to extreme wear or to the requirement of constant adjustment.

A further object of this invention is' to release or render inoperative all of the above mentioned features when the transmission is adjusted to move the vehicle in the reverse direction.

With the foregoing and other objects in View, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawing for an illustrative embodiment of the invention, wherein:

Fig. 1 is a vertical section of a conventional automobile transmission embodying th'e present invention.

Fig: 2 -is"a vertical section" taken upon" line 2"20f Fig. 1.

Fig. 3 is a vertical sectionofpartofa con'' ventional automobil'e transmission illustrating'the reverse disconnected position of-this invention:

Fig. 4:- is a-perspective View of the shiftable reverse torquetransmitting -member.

Referring to theaccompanying drawingywhere in. similar parts are designated-' by similar characters-throughout; I iindicates the driving shaftnormally connected to the conventional clutch andvv driven by. the gas .engineoofo the; Vehicle. Character 9 :showsthercountershaft which.rotates..l5 integrally low speed gear 3, and driverrgearrl: which rotatesidler gear 5 shown partlyin dotted lines in Fig. 1. The shiftable low and reverse. gear isintegral withwthe external :clutch-gear 8 and both are comprisedinazzmember generally, designated 1 and illustrated inperspective in Fig. 4. Member 'I is shiftable on thesh'aft 24bit. the low and reverse speed shiftinglver 29, and" rotates shaft 2d by'the'engagement'ofexternalj splines 25 on internal "splines23. These'splines transmit torque from shaft to member "I "and viceversa.

Splines 2| on the driven shaft '22 are connected-- to the universal .joint, not shown, and transmit power to the propeller shaft of the vehicle to drive :the same.

Anaover-running clutch l 2- has an outer rotatablewmember. 13' held to thetransmission housing l5iby pressure exerted by spring. IS on shoeeis .tozfrictionlining H. Member l3 rotates only when sufficient torqueis applied. a

The over-running 'clutch I2 has an inner cam member II and'the.conventionalarollersl4; with which cooperate springs 20 and cam shoes 2|. Internal .clutchgear. I ll occupiesthe entire length i of H; The externalwclutchxgear8, above mentionedgnengagesinternal. clutch gearlll as shown" inqFigl 1;,andfzin figs: 3..they are shown :discon nected.

The over-running clutch I2 is centered by that part of the transmission housing I5 designated as l6, while the brake system exerts pressure on the outer member l3. The brake lining I! may be of the type which is effective in oil and may be of metal integral with shoe I8. Shoe I8 has 50 enough springing action allowing it to move in and take up wear of the lining. Stud 28 is threaded and screws on to the transmission housing and is adjustable by head 26 and locked by lock-nut 21, and provides adjustment for the 55 above mentioned spring. This system keeps the braking pressure on outer member l3 very nearly constant as the lining l1 wears, and eliminates frequent manual adjustments-which would othertakes place during reverse motion of the vehicle if the transmission is set for neutral or any for- :ward speed. In this condition clutch members,

8 and I0 engage, and inner cam'member' ll engages or grips outer member [3 due to the Well known action of the rollers. l4 caused by their wedging between the interior surface of ['3 and the outer ca-m surface of I I The vehicle is thus prevented from reversing under ordinary.

conditions as those caused by the vehicles own weight. If, the vehicle is hit with sufficient force tending to produce reverse motion the brake system.will yield before any other part of the 'hicle.

vehicle, and thus the novel method herein dis closed acts as a protective means. Insofar as the braking effects on I3 are concerned, shaft 24 is free to rotate in the directionrillustrated by the arrow in Fig. 2. This corresponds to the forward'movement of the ve- 7 In this direction, while member 1 rotates ll through the engagement of clutch members 8 and I0, it will not be subjected to resistance, due to the well known freeing feature of. the over-running clutch caused by rollers l4 moving slightly away from the wedging surfaces of members H and I3.

' The transmission is adjusted to cause the vehicle to move in the reverse direction by the movement of lever 29,- shifting member 1, and engaging reverse idler gear 5 to gear 6 and disconnecting clutch members 8 and ID. This is necessary since the above mentioned reverse Various changes may be made in' details of construction by'those skilled in the art without departing from the spirit or scope of the invention as'defined by the appended claims.

I claim: 1 V

1. The combination, in a transmission, of an over-running clutch with, an outer rotatable cylindrical member secured to the transmission housing bythe close fitting interior ofa second.

cylindrical member, means for applying pressure tothe outer rotatable cylindrical member by closing a split section of the second cylindrical member, an inner cam member contained within the said outer rotatable member preventing rehaving an external clutch gear integral therewith and adapted to be engaged with the internal clutch gear of the inner cam memberin all forward speeds and neutral.

2. The combination, in a transmission, of an over-running clutch with an outer rotatable member secured to the transmission housing,

under pressure androtatable by forces exceeding a specified minimum and an inner cam .member rotatable in the direction caused by forward motion, a reverse torque transmitting member internally splined and shiftable'having a gear enageable for low and reverse speed and an eX-,

ternal clutch gear integral therewith, and means on the inner cam member engageable to the external clutch gear of the said shiftable reverse torque transmitting member in all forward 1 speeds and neutral.

3. The combination, in a transmission, of an over-running clutch withan outer rotatable reverse speed and an external clutch gear integral therewith, and an internal clutch gear on V the inner cam member engageable to the 'external clutch gear of the reverse torque transmitting member and the internal clutch gear having a width greater than the total movement of the said shiftable reverse transmitting member from neutral to low speed'position and the,

width of the external clutch gear, and conveying reverse resistance thereto in these positions;

4..The combination, in a transmission, of

means utilizing a brake shoe for providing perma-V' nent braking pressure, means for maintaining said braking pressure constant, an over-running clutch with its outer rotatablemember held by the said braking pressure and an inner cam member rotatable; in the direction caused by forward motion and having an internal clutch gear,

a reverse torque transmitting member internally splined and shiftableon the transmission shaft and having an external clutch gear integral therewith and engageable to the said internal clutch gearin all forward speedsand neutral. 7

5. The combination, in a transmission, of a brake shoe providing brakingraction, a spring bearing on the said shoeto provide braking pres- H I sure and adjustable by a threaded stud, an overrunning clutch with an outer rotatable member held by the said brakingaction and an inner member rotatable in'the direction caused by forward motionand having an internal clutch gear integral therewith, and a reverse torque trans-V mitting member internally splined and shiftable on the transmission shaft having an external clutch gear integral therewith and engageable to the said internal clutch gearin all forward speeds and neutral. 1

ARNOLD LESTI. 

